The predicted primary structure of the measles virus hemagglutinin

The complete nucleotide sequence of cloned cDNAs corresponding to the full length of the mRNA encoding the measles virus hemagglutinin (H) protein has been determined. the mRNA contains a single large open reading frame which is capable of encoding a protein of 617 amino acids with a molecular mass of 69,250 Da. The deduced amino acid structure of the protein indicates that the only major hydrophobic region of sufficient length to anchor the molecule in membranes is located near the amino terminus. Comparison of the amino acid structure of the measles virus H protein with that of the hemagglutinin-neuraminidase (HN) molecules of Sendai virus and simian virus 5 (SV5) reveals little homology. However, 11 of the 13 cysteine residues found in the measles H protein can be aligned with cysteines in the Sendai virus HN protein in similar positions relative to one another. Five potential N-linked glycosylation sites are present in the measles H protein sequence. These are relatively closely grouped between amino acids residues 168 and 240 in the amino terminal half of the molecule. No obvious structural features are present in the measles H protein amino acid sequence which might explain the reported absence of neuraminidase activity associated with the molecule.